In the ethanol industry, sugars and/or starches and/or carbohydrates are extracted from biological materials such as corn, grasses, switch grass, corn stover, or other lignocellulosic biomass containing sugars and/or starches. The extracted sugars and/or starches are then fermented to convert them to ethanol, and the mixture may be distilled to remove the ethanol. Historically, sugars and starches have been extracted by soaking biological materials, such as corn, in a mixture of water and perhaps a substance to help leach out the sugars and starches such as an acid, a caustic, enzymes, and the like. The more material that can be extracted or leached, the higher the yield for a given amount of biological material. There is a need for a more efficient method of extracting or leaching sugars and/or starches and/or carbohydrates from biological feed materials that produces higher yields. It is to the provision of such a method and an apparatus for carrying out the method that the present invention is primarily directed.